The present invention relates to an inkjet printer, and particularly to an inkjet printer utilizing white ink.
When an inkjet printer prints an image on a recording medium, a carriage installed a recording head is moved to scan the recording medium in the direction approximately perpendicular to the moving direction of the recording medium, and during scanning movement of the recording head, an ink is jetted from the recording head.
In cases where an image is printed on a recording medium having white recording surface such as paper, the recording surface is already white even before printing, therefore, it is possible to print characters, signs and images in various colors without need to apply a white image printing. However, in cases where white printing is required on a recording medium with a recording surface (for example black recording surface) other than white (hereinafter called a colored recording medium), or on a recording medium such as transparent or semitransparent resin film (hereinafter called a transparent medium), an inkjet printer capable of white image printing is necessary. For example, at positions for part mounting on a printed circuit board used in the semiconductor industry, characters, signs and lines are white image printed by using an inkjet printer capable of white image printing.
In cases where printing is conducted on a recording medium such as a colored recording medium or transparent medium, when a conventional inkjet printer is used, white color density of the white ink is not high enough, therefore, in order to increase the covering power of the white ink, multiple printings used to be required, or there were cases in which white printing was applied to produce a white background. In these cases, the amount of consumption of white ink, which consists of only white ink, may be 5 to 10 times the consumption of each process color ink of yellow (Y), magenta (M), cyan (C) and black (K) inks. Consequently, the frequency of exchanging the ink tank storing white ink needs to be increased, and this may result in an increase of user""s labor and non-improvement of working efficiency.
Accordingly, the present invention provides an inkjet printer which decreases user""s labor and improves working efficiency while conducting white printing.
The structures to solve the abovementioned problems are:
(1) An inkjet printer provided with a white tank for storing white ink, and process color tanks for storing respective process color inks, characterizing in that a capacity of the white tank is larger than a capacity of each of the process color tanks.
According to the structure (1), a larger volume of white ink can be stored than each volume of respective process color inks, since the capacity of the white tank is larger than the capacity of each of the process color tanks. Therefore, even in cases where white background is printed at an image printing area on a recording medium such as colored medium and transparent medium (or a large volume of white ink is consumed by printing), and consumption of white ink becomes larger than consumption of each process color inks, the frequency of exchanging white color tank can be suppressed and this result in decrease of user""s labor and improvement of working efficiency.
(2) The inkjet printer according to (1), wherein the white tank and the color tanks are respectively provided with a main tank, which can store a large volume of ink, and a sub-tank with smaller capacity for temporarily storing ink from the main tank, characterizing in that at least either the capacity of the main tank or the sub-tank in the white tank is larger than the respective capacity of main tank or sub-tank in each of the process color tanks.
According to the structure (2), a larger volume of white ink can be stored in at least either the main tank or the sub-tank of the white tank, than the respective main tank or sub-tank of the process color tanks, therefore, a similar effect as the effect of (1) can be attained.
(3) The inkjet printer according to (1) or (2), wherein each of the white ink and the process color inks is UV ink which is hardened by exposure of UV (ultra violet light).
The UV ink is an ink that hardens to solid state from liquid state by a photochemical reaction caused by UV radiation. The UV ink is a self-fixing type ink, and is characterized in being capable of fixing onto various media which are not inkjet exclusive media processed for inkjet printing.
(4) The inkjet printer according to any one of (1) through (3), characterizing in that a heating means (device) is provided for controlling the ink temperature in each of the sub-tanks.
According to the structure (4), since the ink temperature in sub-tanks can be controlled, the ink to be jetted onto the recording medium can be kept in a preferable temperature condition. This leads to improvement of printed image quality.
(5) The inkjet printer according to any one of (1) through (4), characterizing in that a recording medium, on which an image is recorded with the white ink and each of the process color inks, is one of a transparent resin film and a semitransparent resin film.
In this case, since the recording medium is transparent or semitransparent, both top face printing, which makes printed surface on the top surface, and a bottom face printing, which makes printed surface on bottom surface, are possible.